4 BOTANICAL GAZETTE [januaky 



from which firmly coherent, simple, parallel sporogenous elements 

 arise vertically, forming an even hymenial surface, the contents of 

 the upper portion of each element becoming separated to form a 

 single row of endogenous, simple, hyaline spores, which are dis- 

 charged through a terminal perforation; the peripheral elements 

 sterile, dark, indurated, forming a well defined rim or exciple; 

 the margin in contact with the substratum slightly spreading and 



lichenoid. 



This structure, which characterizes the mature condition of 

 this very remarkable type, two species of which have been examined 

 from living Termites, appears to be a secondary development, 

 which results from the vertical proliferation of a primary stage 

 similar to that represented in figs. 6 and 13. This primary con- 

 dition may be more or less elongated or orbicular, varying to some 

 extent according to the position of growth; it is formed by a 

 continuous layer of slightly brownish cells, the whole reducible to 

 a copiously branched and septate filament, the branches of which 

 are in lateral contact, the ultimate branchlets forming a radiate 

 lichenoid margin. As the cells mature and enlarge, there may be 

 more or less displacement, as a result of which the fundamental 

 arrangement of the cells in branching filaments may be obscured or 

 obliterated. The general appearance of this stage, as represented 

 in the figures cited, recalls that of some species of Asterina or of a 

 young Aglaozonia or some species of Coleochaete, the resemblance 

 to the latter being rendered more realistic by the presence of the 

 projecting bristles of the host, which are completely surrounded 

 by the advancing margin and are left projecting from the thallus 

 without displacement. Of the cells which form this primary incrust- 

 ing layer, many usually become characteristically modified (fig. 13), 

 assuming the appearance of chlamydospor es , which are clearly dif- 

 ferentiated from the unmodified cells about them by their greater 

 size, thicker walls, more rounded outline, and deep brown color. 

 Whether these bodies are ever separated and become functional 

 spores it has not been possible to determine, although various in- 

 stances have been seen in which they appear to have been dislodged. 



The preliminary stage just described has been seen in only a few 

 cases, and a complete series, showing the transition from this to the 



